Understanding Chronic Migraine

Written by Kimberly Holland | Published on July 1, 2014
Medically Reviewed by George T. Krucik, MD, MBA on July 1, 2014

Migraines are a deeply painful, often debilitating form of headache.

Episodic vs. Chronic Migraine

Migraines are a deeply painful, often debilitating form of headache. People who experience migraines often require prescription medication or medical treatments in order to cope with their symptoms. A simple over-the-counter headache pill is rarely effective for treating migraine. 

Migraines can be episodic or chronic. A typical episodic migraine (EM) can linger for hours. Several weeks or even months may pass between migraine episodes.

When a Migraine Is No Longer Just a Migraine

Then there’s the type of migraine that lingers for many days and even weeks. Chronic migraines (CM) are migraine headaches that last longer and occur more frequently. Some people who experience EM will eventually develop CM, but not all. A few defining characteristics separate EM from CM.

Symptoms of a chronic migraine occur at least 15 days in each month. Headaches must also occur 15 or more days in at least three consecutive months. A chronic migraine must also involve two of the following migraine characteristics for a minimum of eight days in a month:

  • The headache causes moderate to severe pain.
  • The headache predominantly affects one side of the head.
  • The headache causes a throbbing, pulsating sensation in the side of the head (brain) affected by the headache.
  • The headache begins or is made worse due to routine physical activity, such as walking or cleaning.

How Common Are Chronic Migraines?

According to an American Migraine Prevalence and Prevention (AMPP) study, 17.1 percent of American women and 5.6 percent of American men have EM. EM is much more common than CM. Only 1.3 percent of American women have CM, and 0.5 percent of American men experience CM.

What Causes Chronic Migraine?

Unfortunately, migraines are not understood well by doctors and researchers. Possible causes have been identified, but definitive answers have not yet been discovered.

Some theories as to what causes migraine include:

  • central nervous system disorder: An underlying neurological condition might trigger chronic migraines.
  • chemical imbalances: Proper brain function requires all chemicals be evenly matched and all nerve pathways clear. In the event any of these things are interrupted, migraine headaches may occur.
  • genetic factors: If a close family member, such as a parent or sibling, has experienced migraine headaches, your chances of having migraines increases.
  • vascular irregularities: Problems with the shape, size, or flow of blood vessels flowing to or inside your brain may cause migraine headaches.

What Can Trigger Migraine?

Migraine triggers are different than migraine causes. People who are susceptible to migraines, or individuals who have had a history of migraines, may find that certain situations, behaviors, or environments set off a new migraine episode. These factors are called triggers.

Triggers are different for each person. Also, triggers may affect people differently each time they’re exposed. For patients with CM, avoiding common migraine triggers may help reduce the likelihood of a flare-up of symptoms.

The common triggers for migraine include:

  • anxiety and stress: People who have a history of migraine may find that painful headaches flare up during times of increased stress and anxiety.
  • bad posture: How you sit may affect how you feel. Poor posture can reduce blood flow through your neck. This reduced blood flow can also potentially cause a migraine headache.
  • caffeine use and abuse: The stimulant can potentially trigger a migraine episode. Additionally, the high-sugar sodas or drinks that contain caffeine can trigger migraines, too.
  • food and drink: Salty, spicy, and aged foods (such as cured meats and cheeses) may cause CM. Artificial sweeteners found in some diet foods can also trigger CM. Monosodium glutamate (MSG) is a common food preservative that has been shown to trigger migraine headaches, too.
  • hormones: Both EM and CM are more common in women than men. This may be because women experience regular hormonal changes as a result of menstruation. Women also experience dramatic hormone shifts before and during menopause. Hormonal medications, including birth control, can also trigger CM.
  • medications: Vasodilators affect your vascular system, or blood vessels. A vascular problem can trigger a migraine or make one worse. Because vasodilators can change your blood vessels, they may trigger CM.
  • headache medication: If you take over-the-counter headache medication more than three days each week or more than nine days in a month to treat your migraines, you may experience rebound migraines. Your doctor can help advise regarding the best way to treat your migraines with medication.
  • sensory stimulation: Flashing lights, loud music, and strong odors may trigger a migraine headache episode.
  • sleep difficulties: Not getting routine sleep may cause bags under your eyes, but it may also cause a chronic migraine episode. On the other hand, too much sleep might also cause a migraine.
  • weather: Shifts in temperature, humidity, and barometric pressure can affect your migraine status.

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